<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="selectAllInputComputed"/>
    </label>
    <span>
          <span>已完成{{isDoneSelectComputed}}</span> / 全部{{allTodosComputed}}
        </span>
    <button class="btn btn-danger" @click="delAllisDone">清除已完成任务</button>
  </div>
</template>

<script>
  export default {
    name: "TodoFooter",
    props: ['todos','selectAll','delAllisDone'],
    computed: {
      isDoneSelectComputed() {
        return (
          this.todos.reduce((pre, item) => {
            return pre + (item.isDone ? 1 : 0)
          }, 0)
        )
      },
      allTodosComputed() {
        return this.todos.length
      },
      selectAllInputComputed: {
        get() {
          return this.allTodosComputed > 0 && this.allTodosComputed === this.isDoneSelectComputed
        },
        set(newVal) {
          this.selectAll(newVal)
        },
      }
    }
  }
</script>

<style scoped>
  /*footer*/
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }
  
  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }
  
  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }
  
  .todo-footer button {
    float: right;
    margin-top: 5px;
  }

</style>